Production of incandescent-electric-lamp filaments.



TA ES- PATENT'OFFICE.

WALDEMAR 1811mm}, or mum, GERMANY, ASSIGNOR "r IHERMANN MALA- cuowsxl, or BERLIN, GERMANY.

PRODUCTION OI INANDESCENT-ELECTRIC43AM?; FILAMENTS.

973,883. Io Dal ring.

l'oall whom it may concerni.

a subject of the King of Ii'ussiar'aml ream ing at Berlin, Germany, have invented a certam new and .useful Improvement in the Production of Incandesceiit-Eleetriollamp Filaments, of which the following is a specification.

Thepl'esent in'vent-im'i relates to tl1e 'pro-' duction of filaments for incandescent electric lamps, particularly forlampsof low current requirement. The lamp filaments are of -('a1'- v bon coated with an element 'of'the antimony"- arsenlc group, that is to say', coated with either antimony or arsenic.

p The proeess of making the filaments may be carried out as follows: The carbon tilamerit, preferably one madeby the eh-loi'id of .ZlIlC process is first treated with acetic acid emcoon and then .glowed or heated to a red heat lnantunol'ifvhydrogen gas (SblfL-J 0r arsen c hydrogen gas (AsH [whereby antimony 'or arsenic, as' the case may be, is deposited .upon, the' -filament.

This;preparatory treatment may take place I in aISpec-ial-receptacle )or in the lamp bull)- itself. To increase the illuminating power. of the tilanient', -a drop"of 'mercury maybe introduced into-the tube, whi'clr'lsthen. subjected to the exhausting p rocess, -nntii l" as high a \-'ae'|u-n'n possible-is obtained." In. case mercury is tl n|s' en ip lo yed i-the filament eovered' with the element of the antin'iony-arsenie .gro'up described is given a treatment wlth ca'rbureted" l 1ydrogen Ill order vto'fdep'oslt on the ant mony jo'r arsenie"eoating a layer ofearlmn; whi'eh protects the arsenic orantimony eoatmg from the 'amal' amatin' or oxidizin ,efi'eet Speeiflcatiou of Letters Patent. Application filed November. 15, 1909. Serial No. 528,152;

Patented Oct. 215, 19.1.0

.theexhaustiou. the more'rpiiekly does the mercury evaporate after the current is turned .01 and the more quit-kl) does the filament get up to'its't'ull illuminating power.

The coating of antimony or arsenie de-' posited on the carbon filament is not Volatile but serves to prevent a loosenii'ig of the. partieles of carbon, Of'WhlCll the body of the aearbonfilamei'ltwith a (eatingContaining an element of the-'antimoiiy-arsenic group deposited thereon and an outer. layer of vcarbon.

I of the inereury Vapor, Th more complete a Be it" known that I, \Vam mma Ri'ntukn 4. An incandescent :ele e-tric lamp, having 1 axcar'bon filament w th a coatingeonslstlng of an element of-the antim'olrv-ilrsenic group deposited thereon andlan outer layer of carbon.

. An iIncandescent; eleetrie. lamp, having a carbon f lament wlth a coating of. antln'iony' .deposited 't'here m'i' and an. outerlayer of 1a testimony whereof ;I have signed '.'1 ny name to this specification, the preseneeof twosubseribing w1ti'iessesijv 

